The disparity in ischemic stroke mortality risk between black and white children in the U.S. has diminished over the past decade, and a study published in the August issue of JAMA Pediatrics found that the change may be due to the use of long-term blood transfusion to prevent strokes in children with sickle cell disease.

The use of transfusion to prevent strokes in high-risk children was first studied during the Stroke Prevention Trial in Sickle Cell Anemia (STOP Trial), carried out at 14 trial centers from 1995 through 1997, when the study was stopped early. The study included 1,934 children ages 2 to 16 with sickle-cell anemia or sickle beta-thalassemia who had no stroke histories.

The STOP trial found that long-term transfusions decreased stroke risk by more than 90 percent among children identified as high risk by Doppler ultrasound screening.

‘We hypothesized that the ethnic disparity in childhood stroke mortality has diminished since the publication of the STOP trial in 1998,” wrote the authors of the current study, Laura L. Lehman, MD, of Boston Children’s Hospital in Boston, and Heather J. Fullerton, MD, of the University of California, San Francisco.

Lehman and Fullerton accessed death certificate data from the National Center for Health Statistics (NCHS) for all U.S. children from 1988 through 2007.

There were more than 1 billion person-years included in the study cohort. Black children comprised 16 percent of the population. The primary cause of death was stroke in 4,425 deaths, 20 percent of which were ischemic strokes. For study purposes, the researchers included young people younger than 20 years of age.

“The excess risk of ischemic stroke mortality in black vs white children decreased by almost two-thirds, from 74 percent (1988-1997) to 27 percent (1998-2007),” the authors wrote.

There was no change in mortality risk for hemorrhagic strokes throughout the study period, which was expected, since ischemic strokes are the most common type of stroke among children with sickle cell disease.

While the data do not definitively link long-term blood transfusions with the diminishing disparity in mortality, the authors noted that starting this therapy was the only major change in pediatric stroke care over the course of their research.

However, they also explained that the narrowing disparity began before the STOP trial was published, so there could be other explanations as well.

One important limitation of the study, they acknowledged, was the use of NCHS data. They were unable to say whether the decline in stroke mortality was caused by a decrease in fatalities or decreased incidence.

In an accompanying editorial, Lori C. Jordan, MD, and Michael R. DeBaun, MD, of Vanderbilt University Medical Center in Nashville, Tenn., wrote that although the study was not able to assess whether the racial differences in stroke mortality exist among children without sickle cell disease, it highlights the importance of addressing racial and ethnic health disparities in pediatric populations.

“Ultimately, the goal is to provide targeted prevention and treatment strategies specific to the different causes of strokes in children,” Jordan and DeBaun wrote.